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Re: No Hedging.
>On Wed, 20 May 1998, chris brochu wrote:
>> This quote indicates some ignorance on Hedges' part
>> This quote by Hedges, by the way, is not surprising, given some of the
>> other papers Hedges has authored or coauthored on the subject of
>> molecules-versus-morphology. Most of the systematics community have come
>> around to saying "molecules or morphology? Yes!", but he is one of those
>> who would still favor one over the other.
>Which of Hedges' statements is ignorant?
>1. Paleontologists hardly ever look for mammals in C. rocks?
This is precisely it. There's a large body of literature on Mesozoic
mammals, dating back to Richard Owen. I've personally worked with the
people looking for Late Cretaceous mammals - there are more than you think.
And new Cretaceous mammal fossils are being described all the time.
>Is there a bias in dollars going to dinosaur research versus
>pre-K/T mammal research?
I don't know if there's even a difference in funding levels between the
groups. I've personally groused for many years about the dearth of funding
for crocodile paleontology, but that's another matter.
Seriously, though - Late K mammal work is considered very sexy in the
profession and does receive a lot of funding. Those Malagasy dinosaurs
(e.g. Majungatholus) were one part of a broader program, one of which's
stated goals was Late Cretaceous Gondwanan mammals. And I recommend Mike
Novacek's book on the recent Mongolian field seasons (Dinosaurs of the
Flaming Cliffs), which is not only (in my opinion) the best popular book on
dinosaurs ever written, but also clearly states out the author's deep
interest in mammals of that period and place.
Are there rocks which probably don't contain
>dino fossils but might contain mammal fossils? Are they less likely to be
Not today they're not. The techniques are different - screenwashing versus
quarrying, for example. But generally, when old sites are revisited it's
often to find the small taxa (mammals, squamates, amphibians, etc.)
>2. There was previously not enough convincing evidence for paleontologists
>to invest their time searching?
>Does the generally held view that pre K/T mammals lack diversity tend to
>fulfill itself by discouraging research?
This view is not generally held, actually. And this research is not
discouraged (see above).
>3. Paleontologists presume that modern aspect species sprang into
>existence after the K/T so they don't bother to look?
Also not correct - though some recent work does indicate a rapid period of
diversification during the Paleocene, which may be independent of the
molecular data for a variety of reasons.
>By the way, I think Benton's comment about Cretaceous rabbits and
>elephants was intended to be ironic, i.e., he seriously doubts
>the validity of the molecular evidence.
If so, then he was grossly misquoted in the article and its author owes him
- and us - an apology.
>4. Mammals might turn up in previously overlooked strata?
Of course they might - which is why we keep looking!!
>Ultimately, of course, fossils will arbitrate this particular "molecules
>or morphology" argument. But only if a reasonable amount of effort is
>invested. Has this happened? From the outside I see two extreme
>opinions. Hedges saying no one has looked, and others
>saying words to the effect of: "We have found all the pre-K/T mammals we
>are going to find."
Neither of these opinions is accurate, and neither is mainstream.
Christopher Brochu, Ph.D.
Postdoctoral Research Scientist
Department of Geology
Field Museum of Natural History
Lake Shore Drive at Roosevelt Road
Chicago, IL 60605 USA
phone: 312-922-9410, ext. 469